London, June 9 (RHC)-- Ryanair will not cancel British flights despite the beginning of what the boss of Europe's biggest budget airline called a "rubbish" 14-day quarantine for international arrivals.

Ryanair, easyJet and BA-owner IAG have threatened legal action over the quarantine, which they say will cripple the British tourism industry.  Asked by BBC Radio whether Ryanair would cancel July and August flights if the quarantine remained in place, group CEO Michael O'Leary said: "No, because the flights are full outbound of the UK. British people are ignoring this quarantine, they know it's rubbish."

The three airlines have sent a "pre-action protocol letter", which can be followed by legal action, in the most vociferous clash between the UK government and the industry since the pandemic began.

Airlines have warned it could deter British travellers, some of the top spenders, from flying to Europe and prevent Europeans from visiting cities such as London and Edinburgh and sites including Stonehenge.

There were 41 million visits to the UK in 2019, according to the national tourism agency, with visitors spending $36 billion and supporting millions of jobs.